Thursday, June 21, 2012
The last time I taught water law, I took my students on an urban water quality field trip. We toured a wastewater treatment plant and visited some impaired urban streams. It was all interesting, or at least the students humored me and pretended it was, but the most memorable moments of the trip involved combined sewer overflows. During the wastewater treatment plant tour, we saw the point where excess sewage flows were diverted into a pipe discharging directly into Casco Bay, not far from a public beach. During our visit to the impaired stream, we stopped not far downstream from a still-active CSO. To untrained eyes, nothing would have seemed amiss with the stream, at least until one student noticed a piece of toilet paper suspended from an overhanging branch, fluttering gently in the October breeze.
CSOs are kind of fascinating. The Clean Water Act assumed its modern form four decades ago, and in the years since we’ve made great strides in controlling direct effluent discharges. Yet in many cities—particularly older ones—combined sewer systems carry stormwater and wastewater to treatment plants, and when storms overwhelm the capacity of those plants, huge volumes of untreated sewage discharge directly to surface waterways. These discharges are blatantly inconsistent with the Clean Water Act, and they impact some highly valued, widely used waterways—often in cities otherwise known for their liberal and green politics. Yet they’re still around.
The primary reason, of course, is money. Avoiding CSO discharges often means major infrastructural improvements, and cash-strapped cities don’t have the money to make those changes quickly. So, while EPA has entered into consent decrees with many cities, and while those cities are slowly chipping away at their CSOs, much work remains to be done. Where I live, at least, while environmental groups aren’t happy with the situation, they grudgingly understand the slow progress. “Yeah, we could sue the city on this,” one prominent Maine environmental attorney told me (I’m paraphrasing) not long ago. “But what are they going to do? Shut down the schools to pay for it?”
In recent years, another complication has emerged. The traditional way to fix a CSO problem was to separate the storm and wastewater sewer systems. Stormwater then would discharge directly to surface water bodies, and with only wastewater going to the treatment plant, the plant’s capacity wouldn’t be overwhelmed. But urban stormwater isn’t exactly benign. It’s loaded with pollutants, and spikes in flow can also damage the hydrology of streams. During smaller storm events—events that would not overwhelm the capacity of treatment systems—a combined sewer system would result in treatment of that stormwater, but with a separated system, such treatment no longer occurs. So while separating the sewers can reduce wastewater pollution, the price is an increase in stormwater pollution.
Last week, EPA released a policy statement designed to address this dilemma. The broad goal of the policy statement is to encourage municipalities to generate integrated plans addressing stormwater and wastewater. A closely related goal is to encourage the use of “green infrastructure”—that is, green roofs, stormwater infiltration systems, and other mechanisms for reducing stormwater discharges--thus reducing strain on combined sewer systems without increasing direct stormwater discharges. EPA isn’t saying that municipalities with these plans will obtain any exemptions from their consent decrees or other Clean Water Act obligations. But EPA does suggest that if municipalities adopt these plans, EPA will take the olans into account when deciding whether to bring enforcement actions, and also when deciding what actions it will require of cities, and what compliance schedules it will negotiate or impose.
One policy statement does not fix a major and longstanding problem. But this sure looks like a step in the right direction, and it’s not the first step EPA has taken to push green infrastructure. Even if the change will be incremental, hopefully there will come a time, not too far in the future, when my water quality field trip is primarly about green roofs and other sustainable stormwater treatment systems (we'll still also go to the wastewater treatment plant), and our sidetrip to the now-defunct CSO just provides a little historical color.